whiting and henry pickford



FICE@ WM. WHITING AND HENRY PIOKFORD, OF BOSTON, MASSACHUSETTS.

LOCK.

Specification of Letters Patent No. 16,892, dated March 24, 1857.

To all 'whom t may concern.'

Be it known that we, WILLIAM VVHITING, of Roxbury, in the county of Norfolk and State of Massachusetts, and HENRY PICK- FORD, of Boston, in the county of Suffolk and State aforesaid, have invented certain new and useful Improvements in Permutation-Locks, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, making part of this specification, in which- Figure 1 is a view of a door lock the top plate being removed to show the parts within, the bolt being shot or locked. Fig. 2 a view of the same unlocked. Fig. 3 the lock with the slides and tumblers removed. Fig. 4 a view of the lock with the top plate on. Fig. 5 a view of the key.

In that class of locks known as permutation locks, or those which are operated by keys having adjustable bits of varying lengths the slides have heretofore been held when the lock was locked, at specific points by means of notches or slots whose distances apart corresponded with the difference in the lengths of the bits on the key necessitating an accurate movement of the parts and consequently rendering the lock expensive.

To obtain a lock that is cheap and simple in its construction and not limited in its changes to any specific arrangement or length of the bits on the key is the object of our present invention which consists in holding the slides in the exact position to which they have been raised by the tumblers when the look is locked by means of pressure as will now be more fully explained.

In the said drawings A is the bolt from which rise the pins a between which the slides B play; these slides are of a suitable number to correspond with the number of the tumblers C which slide up and down on suitable ways (Fig. 3) and are steadied in their place by a stump c which passes through a slot CZ in each tumbler, the levers D and springs E serve to keep the tumblers down when not raised by the key. Each slide B has projecting from its rear edge an arm F which ts into a corresponding recess Gr in its tumbler, and from its front edge a pin e which when the bolt is shot indents itself into a block of india rubber H secured to the backplate of the lock thus retaining each slide B in the exact position in which it was left by its tumbler.

To prevent the bolt from being forced back so that the arms F shall touch the tumblers, we have adopted the following device: I is a spring (seen dotted in Figs. l, 2 and 3,) which is secured to the outside of the back plate, to this is attached a stud f and a pin g (Fig. 3,) which projects through suitable holes in the plate, when the bolt is locked this pin enters a hole L in the bolt and holds it secure from being forced back, when the bolt is withdrawn the pin enters a hole n, and the spring I returns to its place.

The key Fig. 5 attached to the barrel K is a permanent bit z' with which the bolt is shot, and movable bits m which slide onto a pin (seen dotted) attached to the bit c', the bits m may be transposed in their places or may be shortened at pleasure by filing off or otherwise.

Operation: The key being inserted and turned in the lock Fig. l, the outer edge of the bit z' presses down the stud f and with it. the pin g setting free the bolt A, as the key is turned each bit m raises its corresponding tumbler O against the pressure of its lever D, and with the tumbler its slide B; as the bolt is shot forward by the keys the pin e attached to each slide indents itself into the block of india rubber H, the latter by its pressure against the slide holding it in the position to which its tumbler has raised it; then as the key continues to turn the tumblers are relieved from the bits m and are thrown down by their springs E and levers D into their normal position leaving the bolt locked as in Fig.. l. The pin g rising into the hole h near the rear end of the bolt and the stud O entering the notch 29 serve to hold the bolt securely that it cannot be forced back.

In lieu of the block of india rubber H any other suitable elastic substance may be used to hold the slides B in place, or these` slides may be held by pressure applied to th-e top one by a spring L (seen dotted in Fig. 4,) which is secured to the inside of the to-p plate; or by a wedge or inclined surface; or by a cam.

In place of the pins e notches may be made in the edge of each slide B.

It is evident that in the above described is constructed as follows lock the relative position of the slides B may be varied in the most minute degree, the pins e forming for themselves new indentations or holding places in the elastic block; this would not be the case did the pins enter slots or holes made at specific distances in a metal bearing. Should either of the other devices which We have enumerated such as the spring; face or the cam be used, it will offer the same facility for minute adjustment of the slides B. Thus as the variation in the position of the slides is in no Way restricted, the key may be varied not only by changing the relative position of the bits m but by the inclined sur' ling off or shortening one or more of them thus obtaining an entirely new combination, and consequently additional security.

What We claim as our invention and desire to secure by Letters Patent is- Holding the slides in the exact position to which they are raised by the tumblers, by the pressure of an elastic cushion or its equivalent in the manner substantially as herein set forth.

"WILLIAM VVHITING. HENRY PICKFORD. Witnesses SAM. COOPER, P. E. TESCHEMACHER. 

